I am not aware of any political decisions made in this sense. Carbon pricing mechanisms, like the federal system you have before you, ensure that the direct revenue generated by the instrument are returned to the provinces or to designated persons in the province, as my colleagues mentioned earlier.
The carbon pricing systems currently in place, be it in Quebec, Ontario, Alberta or British Columbia, generally end up as part of the price of a litre of gasoline, for example. The GST is applied on that amount and the provincial part of the HST, if any, of course, is returned to the provinces. The GST is outside the current debate on Bill C-74.